Cutting tools for performing machining operations generally comprise a removable cutting insert mounted in the tool. The cutting insert is clamped to the tool so that the cutting edge of the insert protrudes to engage with a workpiece.
During machining the cutting edge becomes worn and the cutting insert will eventually need replacing. The harder the material used in the insert the longer the insert can be used before the wear is sufficient that the insert must be replaced. The hardness of the insert is directly related to the working temperature and as the working temperature rises there is an associated reduction in hardness, and a consequent increase in the rate of wear.
To extend the life of the cutting insert it is therefore known to provide a flow of coolant to the cutting edge of the insert. The coolant also acts to lubricate the interface between the cutting edge and the workpiece and to break up and remove any swarf, which may cause damage to the insert, the work piece or both.
As there is limited space between the cutting insert and the workpiece into which the coolant can be injected it is preferred to feed the coolant through the tool to the cutting insert.
Cutting tools are known in which coolant passes through the tool and is directed to the cutting face of the insert. The coolant passes through the tool into a block, known as a coolant inducer, which is fastened above the cutting insert. The inducer has a fluid passage therethough and directs the coolant to outlets adjacent the cutting face of the insert.
U.S. Pat. No. 5,340,242 discloses an arrangement in which a cutting tool has an inducer 30 described as an orifice cap. The orifice cap 30 directs a high velocity stream at the cutting edge 22 to break a chip of material removed from the workpiece. A discharge orifice 42 in the orifice cap 30 directs the fluid stream just above the cutting edge of the insert 20. A cap screw 44 allows the orifice cap 30 to move to adjust the direction of the fluid stream exiting from the orifice 42.
To improve the efficiency of the cutting tool the coolant should be delivered close to the cutting face of the insert. To achieve this the inducer extends over at least a portion of the cutting insert.
With this arrangement, the inducer must be fastened securely to the tool to prevent relative movement or leakage of the coolant from between the inducer and the tool. This results in problems when the cutting insert needs to be replaced. The fasteners and the inducer have to be removed to allow the insertion of a new cutting insert. This causes delays in the production process and parts may be lost or damaged when they are removed.
The present invention seeks to provide an improved cutting tool having a coolant inducer that may be easily released to allow replacement of the cutting inserts when necessary.